An Investigation on Rheology of Peroxide Cross-linking of Low Density Polyethylene

One of the most important post-reactor modifications of polyethylene is cross-linking. It improves some properties of polyethylene such as environmental stress cracking resistance, chemical and abrasion resistance, and service temperature. In this study, the effect of peroxide cross-linking on the rheological behaviour of low density polyethylene was investigated by using a combination of creep test and differential scanning calorimeter (DSC) in isotherm condition.

The used peroxide was di-cumyl peroxide and its concentration was 2 wt%. The experiments were carried out at 150,160, and 170 degrees C and the change of bulk viscosity due to network developing was determined. For delivering of local derivatives smoothing techniques were applied on creep data. The rate of increment of viscosity increased with increasing the temperature, and the major of this increment took place in the first stages of reaction.